About: http://webisa.webdatacommons.org/343333376

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	In natural substances such as herbs, the strength of the active ingredients can vary, so it was hard to tell how much of it you could give to a patient.
http://www.w3.org/ns/prov#wasQuotedFrom	sciencemuseum.org.uk